Working fluid for heat cycle, composition for heat cycle system, and heat cycle system

ABSTRACT

To provide a working fluid which has cycle performance sufficient as an alternative to R410A while the influence over global warming is sufficiently suppressed, which does not significantly increase the load to an apparatus as compared with a case where R410A is used, and which can be stably used continuously without any special measures, a composition for a heat cycle system contains the working fluid, and a heat cycle system employs the composition. A working fluid for heat cycle, wherein the global warming potential is less than 300; the product of the relative coefficient of performance and the relative refrigerating capacity is at least 0.820 relative to R410A in a standard refrigerating cycle under conditions of an evaporation temperature of 0° C., a condensing temperature of 40° C., a supercoiling degree of 5° C. and a degree of superheat of 5° C.; the relative compressor discharge gas pressure is at most 1.100; the lower limit of the combustion range by method A in High Pressure Gas Safety Act is at least 5 vol %; and the pressure will not exceed 2.00 MPaG in a combustion test by method A in High Pressure Gas Safety act under 0.98 MPaG at 250° C.

TECHNICAL FIELD

The present invention relates to a working fluid for heat cycle, acomposition for a heat cycle system comprising the working fluid, and aheat cycle system employing the composition.

BACKGROUND ART

In this specification, abbreviated names of halogenated hydrocarboncompounds are described in brackets after the compound names, and inthis specification, the abbreviated names are employed instead of thecompound names as the case requires.

Heretofore, as a working fluid for a heat cycle system such as arefrigerant for a refrigerator, a refrigerant for an air-conditioningapparatus, a working fluid for power generation system (such as exhaustheat recovery power generation), a working fluid for a latent heattransport apparatus (such as a heat pipe) or a secondary cooling fluid,a chlorofluorocarbon (CFC) such as chlorotrifluoromethane ordichlorodifluoromethane or a hydrochlorofluorocarbon (HCFC) such aschlorodifluoromethane has been used. However, influences of CFCs andHCFCs over the ozone layer in the stratosphere have been pointed out,and their use is regulated at present.

Under the above conditions, as a working fluid for a heat cycle system,a hydrofluorocarbon (HFC) which has less influence over the ozone layer,such as difluoromethane (HFC-32), tetrafluoroethane or pentafluoroethane(HFC-125) has been used, instead of CFCs and HCFCs. For example, R410A(a pseudoazeotropic mixture refrigerant of HFC-32 and HFC-125 in a massratio of 1:1) is a refrigerant which has been widely used. However, itis pointed out that HFCs may cause global warming.

R410A has been widely used for a common air-conditioning apparatus suchas a so-called package air-conditioner or room air-conditioner, due toits high refrigerating capacity. However, it has a global warmingpotential (GWP) of so high as 2,088, and accordingly development of aworking fluid with low GWP has been desired. Further, development of aworking fluid has been desired on the condition that R410A is simplyreplaced and existing apparatus will be used as they are.

In recent years, a hydrofluoroolefin (HFO) i.e. a HFC having acarbon-carbon double bond is expected, which is a working fluid havingless influence over the ozone layer and having less influence overglobal warming, since the carbon-carbon double bond is likely to bedecomposed by OH radicals in the air. In this specification, a saturatedHFC will be referred to as a HFC and distinguished from a HFO unlessotherwise specified. Further, a HFC may be referred to as a saturatedhydrofluorocarbon in some cases.

As a working fluid employing a HFO, for example, Patent Document 1discloses a technique relating to a working fluid using1,1,2-trifluoroethylene (HFO-1123) which has the above properties andwith which excellent cycle performance will be obtained. Patent Document1 also discloses an attempt to obtain a working fluid comprisingHFO-1123 and various HFCs or HFOs in combination for the purpose ofincreasing the flame retardancy, cycle performance, etc. of the workingfluid. Further, similarly, Patent Document 2 discloses a techniquerelating to a working fluid comprising 1,2-difluoroethylene (HFO-1132).

However, Patent documents 1 and 2 failed to disclose or suggest tocombine HFO-1123 or HFO-1132 with a HFC or another HFO to obtain aworking fluid, with a view to obtaining a working fluid which ispractically useful as an alternative to R410A comprehensivelyconsidering such requirements that the cycle performance such as thecapacity and the efficiency equal to or higher than that of R410A willbe obtained, the load to the apparatus such as the temperature or thepressure at the time of operation will not increase, and the workingfluid can be stably used continuously without any special measures.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: WO2012/157764-   Patent Document 2: WO2012/157765

DISCLOSURE OF INVENTION Technical Problem

It is an object of the present invention to provide a working fluid usedfor a heat cycle system, which has cycle performance sufficient as analternative to R410A while the influence over global warming issufficiently suppressed, which does not significantly increase the loadto the apparatus as compared with a case where R410A is used, and whichcan be stably used continuously without any special measures, acomposition for a heat cycle system comprising the working fluid, and aheat cycle system employing the composition.

Solution to Problem

The present invention provides a working fluid for heat cycle, acomposition for a heat cycle system and a heat cycle system of thefollowing [1] to [10].

[1] A working fluid for heat cycle having the following properties (A-1)to (E-1):

(A-1) the global warming potential (100 years) in IntergovernmentalPanel on Climate Change (IPCC), Fourth assessment report, is less than300;

(B-1) the product of the relative refrigerating capacity (RQ_(R410A))calculated in accordance with the following formula (X) and the relativecoefficient of performance (RCOP_(R410A)) calculated in accordance withthe following formula (Y) is at least 0.820:

$\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{refrigerating}} \\{{capacity}\mspace{14mu}\left( {RQ}_{R\; 410\; A} \right)}\end{matrix} = \frac{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( Q_{sample} \right)}{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu} R\; 410A\mspace{14mu}\left( Q_{R\; 410A} \right)}} & (X) \\{\begin{matrix}{{Relative}\mspace{14mu}{performance}\mspace{14mu}{of}} \\{{coefficient}\mspace{14mu}\left( {RCOP}_{R\; 410A} \right)}\end{matrix} = \frac{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {COP}_{sample} \right)}{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu} R\; 410A\mspace{14mu}\left( {COP}_{R\; 410A} \right)}} & (Y)\end{matrix}$wherein R410A is a mixture of difluoromethane and pentafluoroethane in amass ratio of 1:1, and the sample is a working fluid to be subjected torelative evaluation; the refrigerating capacity of each of the sampleand R410A is an output (kW) when a standard refrigerating cycle isoperated under the following temperature conditions (T) using each ofthe sample and R410A; and the coefficient of performance of each of thesample and R410A is a value obtained by dividing the above output (kW)by the power consumption (kW) required for the above operation usingeach of the sample and R410A;[Temperature Conditions (T)] the evaporation temperature is 0° C. (inthe case of a non-azeotropic mixture, the average temperature of theevaporation initiation temperature and the evaporation completiontemperature), the condensing temperature is 40° C. (in the case of anon-azeotropic mixture, the average temperature of the condensationinitiation temperature and the condensation completion temperature), thesupercooling degree (SC) is 5° C., and the degree of superheat (SH) is5° C.;

(C-1) the relative pressure (RDP_(R410A)) calculated in accordance withthe following formula (Z) is at most 1.100:

$\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{pressure}} \\\left( {RDP}_{R\; 410A} \right)\end{matrix} = \frac{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {DP}_{sample} \right)}{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu} R\; 410\; A\mspace{14mu}\left( {DP}_{R\; 410\; A} \right)}} & (Z)\end{matrix}$wherein R410A is a mixture of difluoromethane and pentafluoroethane in amass ratio of 1:1, and the sample is a working fluid to be subjected torelative evaluation; the compressor discharge gas pressure of each ofthe sample and R410A is a compressor discharge gas pressure when astandard refrigerating cycle is operated under the above temperatureconditions (T) using each of the sample and R410A;

(D-1): the lower limit of the combustion range measured in accordancewith method A in High Pressure Gas Safety Act is at least 5 vol %; and

(E-1) in a combustion test under conditions of 0.98 MPaG and 250° C. inequipment in accordance with method A for measurement of the combustionrange in High Pressure Gas Safety Act, the pressure will not exceed 2.00MPaG.

[2] The working fluid according to [1], wherein the global warmingpotential is at most 250.

[3] The working fluid according to [1], wherein the global warmingpotential is at most 200.

[4] The working fluid according to any one of [1] to [3], wherein theproduct of the relative coefficient of performance (RCOP_(R410A)) andthe relative refrigerating capacity (RQ_(R410A)) is at least 0.900.

[5] The working fluid according to [4], wherein the product of therelative coefficient of performance (RCOP_(R410A)) and the relativerefrigerating capacity (RQ_(R410A)) is at least 0.950.

[6] The working fluid according to any one of [1] to [5], wherein therelative pressure (RDP_(R410A)) is at most 1.000.

[7] The working fluid according to any one of [1] to [6], which has nocombustion range.

[8] A composition for a heat cycle system, which comprises the workingfluid for heat cycle as defined in any one of [1] to [7] and arefrigerant oil.

[9] A heat cycle system, which employs the composition for a heat cyclesystem as defined in [8].

[10] The heat cycle system according to [9], which is a refrigeratingapparatus, an air-conditioning apparatus, a power generation system, aheat transport apparatus or a secondary cooling machine.

Advantageous Effects of Invention

According to the present invention, it is possible to provide a workingfluid to be used for a heat cycle system, which has cycle performancesufficient as an alternative to R410A while the influence over globalwarming is sufficiently suppressed, which does not significantlyincrease the load to the apparatus as compared with a case where R410Ais used, and which can be stably used continuously without any specialmeasures, and a composition for a heat cycle system comprising it.

The heat cycle system of the present invention is a heat cycle systemwhich employs a composition for a heat cycle system which can replaceR410A without any special measures to the apparatus and which has lessinfluence over global warming potential.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic construction view illustrating an example of astandard refrigerating cycle system to evaluate the heat cycle system ofthe present invention.

FIG. 2 is a cycle diagram illustrating the state change of the workingfluid in a refrigerating cycle system in FIG. 1 on a pressure-enthalpychart.

DESCRIPTION OF EMBODIMENTS

Now, the present invention will be described in detail.

[Working Fluid]

The working fluid for heat cycle of the present invention (hereinaftersometimes referred to simply a “working fluid”) has the followingproperties (A-1) to (E-1).

(A-1) The global warming potential (100 years) in IntergovernmentalPanel on Climate Change (IPCC), Fourth assessment report, is less than300. In the following description, the global warming potential willsometimes be referred to as “GWP”.

(B-1) The product of the relative refrigerating capacity (RQ_(R410A))calculated in accordance with the above formula (X) and the relativecoefficient of performance (RCOP_(R410A)) calculated in accordance withthe above formula (Y) is at least 0.820. In the following description,the above product will sometimes be referred to as “relative cycleperformance (relative to R410A)” or simply as “relative cycleperformance”.

(C-1) The relative pressure (RDP_(R410A)) calculated in accordance withthe above formula (Z) is at most 1.100.

(D-1) The lower limit of the combustion range measured in accordancewith method A in High Pressure Gas Safety Act is at least 5 vol %.Hereafter the lower limit of the combustion range will sometimes bereferred to as “combustion lower limit”.

(E-1) In a combustion test under conditions of 0.98 MPaG and 250° C. inequipment in accordance with method A for measurement of the combustionrange in High Pressure Gas Safety Act, the pressure will not exceed 2.00MPaG. “G” following the pressure unit MPa represents the gauge pressure.Hereinafter a property such that the pressure in the combustion testexceeds 2.00 MPaG will be referred to as “self-decomposition property”.

In the present invention, as described above, physical properties of (A)GWP, (B) relative cycle performance (relative to R410A), (C) relativepressure (RDP_(R410A)), (D) combustion lower limit and (E)self-decomposition property are employed as indices, and with respect to(A) to (E), the following conditions (A-1) to (E-1) are required to besatisfied as essential conditions for the working fluid. Now, (A) to (E)will be described.

(A) GWP

GWP is an index to the influence of the working fluid over globalwarming. In this specification, GWP of a mixture is represented by aweighted average by the composition mass. GWP of R410A to be replaced bythe working fluid according to an embodiment of the present invention is2088, and the influence of R410A over global environment is significant.On the other hand, GWP of the working fluid according to an embodimentof the present invention is less than 300 as defined by (A-1).

The working fluid according to an embodiment of the present invention isa working fluid which has very low GWP and has little influence overglobal warming as described above, while having substantially the samecycle performance as the cycle performance of R410A as describedhereinafter. GWP of the working fluid according to an embodiment ispreferably at most 250, more preferably at most 200, particularlypreferably at most 150.

(B) Relative Cycle Performance (Relative to R410A)

The relative cycle performance (relative to R410A) is an index to thecycle performance of the working fluid in terms of relative comparisonwith the cycle performance of R410A to be replaced. The relative cycleperformance (relative to R410A) is specifically represented by theproduct of the relative refrigerating capacity (RQ_(R410A)) and therelative coefficient of performance (RCOP_(R410A)) as describedhereinafter. By employing the product of the relative refrigeratingcapacity (RQ_(R410A)) and the relative coefficient of performance(RCOP_(R410A)) as an index, the capacity and the efficiency of theworking fluid can be evaluated in a balanced manner by one index.

The working fluid according to an embodiment of the present inventionhas a relative cycle performance (relative to R410A) of at least 0.820as defined by (B-1). A working fluid which satisfies both the conditions(A-1) and (B-1), can be a working fluid which has cycle performancesubstantially equal to or higher than R410A and which has remarkablyreduced influence over global warming. The relative cycle performance(relative to R410A) of the working fluid according to an embodiment ispreferably at least 0.900, more preferably at least 0.950, particularlypreferably at least 1.000.

The upper limit of the relative cycle performance (relative to R410A) ofthe working fluid according to an embodiment is not particularlylimited.

Here, the cycle performance is performance required when the workingfluid is applied to heat cycle, and is evaluated by the coefficient ofperformance and the capacity. In a case where the heat cycle system is arefrigerating cycle system, the capacity is refrigerating capacity. Therefrigerating capacity (hereinafter sometimes referred to as “Q” in thisspecification) is an output in the refrigerating cycle system. Thecoefficient of performance (hereinafter sometimes referred to as “COP”in this specification) is a value obtained by dividing the output (kW)by the power (kW) consumed to obtain the output (kW) and corresponds tothe energy consumption efficiency. A higher output will be obtained witha low input when the coefficient of performance is higher.

In the present invention, to employ the relative cycle performance(relative to R410A) as the index, a standard refrigerating cycle underthe following temperature conditions (T) is employed. The relativerefrigerating capacity of the working fluid relative to R410A under theconditions is the relative refrigerating capacity (RQ_(R410A)) obtainedin accordance with the following formula (X). Likewise, the relativecoefficient of performance of the working fluid relative to R410A is therelative coefficient of performance (RCOP_(R410A)) obtained inaccordance with the following formula (Y). In the following formulae (X)and (Y), the sample represents the working fluid to be subjected torelative evaluation.

[Temperature Conditions (T)]

Evaporation temperature: 0° C. (in the case of a non-azeotropic mixture,the average temperature of the evaporation initiation temperature andthe evaporation completion temperature)

Condensing temperature: 40° C. (in the case of a non-azeotropic mixture,the average temperature of the condensation initiation temperature andthe condensation completion temperature)

Supercooling degree (SC): 5° C.

Degree of superheat (SH): 5° C.

$\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{refrigerating}} \\{{capacity}\mspace{14mu}\left( {RQ}_{R\; 410\; A} \right)}\end{matrix} = \frac{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( Q_{sample} \right)}{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu} R\; 410A\mspace{14mu}\left( Q_{R\; 410A} \right)}} & (X) \\{\begin{matrix}{{Relative}\mspace{14mu}{performance}\mspace{14mu}{of}} \\{{coefficient}\mspace{14mu}\left( {RCOP}_{R\; 410A} \right)}\end{matrix} = \frac{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {COP}_{sample} \right)}{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu} R\; 410A\mspace{14mu}\left( {COP}_{R\; 410A} \right)}} & (Y)\end{matrix}$

The standard refrigerating cycle system employed for the aboveevaluation may, for example, a refrigerating cycle system of which theschematic construction view is shown in FIG. 1. Now, the method forobtaining the refrigerating capacity and the coefficient of performanceof a predetermined working fluid employing the refrigerating cyclesystem shown in FIG. 1 will be described.

A refrigerating cycle system 10 shown in FIG. 1 is a system generallycomprising a compressor 11 to compress a working fluid vapor A to form ahigh temperature/high pressure working fluid vapor B, a condenser 12 tocool and liquefy the working fluid vapor B discharged from thecompressor 11 to form a low temperature/high pressure working fluid C,an expansion valve 13 to let the working fluid C discharged from thecondenser 12 expand to form a low temperature/low pressure working fluidD, an evaporator 14 to heat the working fluid D discharged from theexpansion valve 13 to form a high temperature/low pressure working fluidvapor A, a pump 15 to supply a load fluid E to the evaporator 14, and apump 16 to supply a fluid F to the condenser 12.

In the refrigerating cycle system 10, a cycle of the following (i) to(iv) is repeated.

(i) A working fluid vapor A discharged from an evaporator 14 iscompressed by a compressor 11 to form a high temperature/high pressureworking fluid vapor B (hereinafter referred to as “AB process”).

(ii) The working fluid vapor B discharged from the compressor 11 iscooled and liquefied by a fluid F in a condenser 12 to form a lowtemperature/high pressure working fluid C. At that time, the fluid F isheated to form a fluid F′, which is discharged from the condenser 12(hereinafter referred to as “BC process”).

(iii) The working fluid C discharged from the condenser 12 is expandedin an expansion valve 13 to form a low temperature/low pressure workingfluid D (hereinafter referred to as “CD process”).

(iv) The working fluid D discharged from the expansion valve 13 isheated by a load fluid E in the evaporator 14 to form a hightemperature/low pressure working fluid vapor A. At that time, the loadfluid E is cooled and becomes a load fluid E′, which is discharged fromthe evaporator 14 (hereinafter referred to as “DA process”).

The refrigerating cycle system 10 is a cycle system comprising anadiabatic isoentropic change, an isenthalpic change and an isobaricchange. The state change of the working fluid, as represented on apressure-enthalpy chart (curve) as shown in FIG. 2, may be representedas a trapezoid having points A, B, C and D as vertexes.

The AB process is a process wherein adiabatic compression is carried outby the compressor 11 to change the high temperature/low pressure workingfluid vapor A to a high temperature/high pressure working fluid vapor B,and is represented by the line AB in FIG. 2. As described hereinafter,the working fluid vapor A is introduced to the compressor 11 in asuperheated state, and the obtainable working fluid vapor B is also asuperheated vapor. The compressor discharge gas pressure (dischargepressure) employed to calculate (C) the relative pressure (RDP_(R410A))as described hereinafter is the pressure (DP) in the state B in FIG. 2and is the maximum pressure in the refrigerating cycle. The temperaturein the state B in FIG. 2 is the compressor discharge gas temperature(discharge temperature) and is the maximum temperature in therefrigerating cycle.

The BC process is a process wherein isobaric cooling is carried out inthe condenser 12 to change the high temperature/high pressure workingfluid vapor B to a low temperature/high pressure working fluid C and isrepresented by the BC line in FIG. 2. The pressure in this process isthe condensation pressure. Of the two intersection points of thepressure enthalpy chart and the BC line, the intersection point T₁ onthe high enthalpy side is the condensing temperature, and theintersection point T₂ on the low enthalpy side is the condensationboiling point temperature.

The CD process is a process wherein isenthalpic expansion is carried outby the expansion valve 13 to change the low temperature/high pressureworking fluid C to a low temperature/low pressure working fluid D and ispresented by the CD line in FIG. 2. T₂−T₃ corresponds to thesupercooling degree (SC) of the working fluid in the cycle of (i) to(iv), where T₃ is the temperature of the low temperature/high pressureworking fluid C.

The DA process is a process wherein isobaric heating is carried out inthe evaporator 14 to have the low temperature/low pressure working fluidD returned to a high temperature/low pressure working fluid vapor A, andis represented by the DA line in FIG. 2. The pressure in this process isthe evaporation pressure. Of the two intersection points of the pressureenthalpy chart and the DA line, the intersection point T₆ on the highenthalpy side is the evaporation temperature. T₇−T₆ corresponds to thedegree of superheat (SH) of the working fluid in the cycle of (i) to(iv), where T₇ is the temperature of the working fluid vapor A. T₄indicates the temperature of the working fluid D.

Q and COP of the working fluid are obtained respectively in accordancewith the following formulae (11) and (12) from enthalpies h_(A), h_(B),h_(C) and h_(D) in the respective states A (after evaporation, hightemperature and low pressure), B (after compression, high temperatureand high pressure), C (after condensation, low temperature and highpressure) and D (after expansion, low temperature and low pressure) ofthe working fluid.

It is assumed that there is no loss in the equipment efficiency and nopressure loss in the pipelines and heat exchangers.

The thermodynamic properties required for calculation of the cycleperformance of the working fluid are calculated based on the generalizedequation of state (Soave-Redlich-Kwong equation) based on the law ofcorresponding state and various thermodynamic equations. If acharacteristic value is not available, it is calculated employing anestimation technique based on a group contribution method.Q=h _(A) −h _(D)  (11)COP=Q/compression work=(h _(A) −h _(D))/(h _(B) −h _(A))  (12)

Q represented by the above (h_(A)−h_(D)) corresponds to the output (kW)of the refrigerating cycle, and the compression work represented by(h_(B)−h_(A)), for example, an electric energy required to operate acompressor, corresponds to the power (kW) consumed. Further, Q means acapacity to freeze a load fluid, and a higher Q means that more workscan be done in the same system. In other words, it means that with aworking fluid having a higher Q, the desired performance can be obtainedwith a smaller amount, whereby the heat cycle system can be downsized.

Further, the relative refrigerating capacity (RQ_(R410A)) and therelative coefficient of performance (RCOP_(R410A)) of the working fluidaccording to an embodiment satisfy the above condition (B-1) and inaddition, the relative refrigerating capacity (RQ_(R410A)) is preferablyat least 0.820, and the relative coefficient of performance(RCOP_(R410A)) is preferably at least 0.960. More preferably, therelative refrigerating capacity (RQ_(R410A)) is at least 0.950, and therelative coefficient of performance (RCOP_(R410A)) is at least 0.980.

(C) Relative pressure (RDP_(R410A))

The relative pressure (RDP_(R410A)) is an index to the load of theworking fluid to an apparatus represented by relative comparison withthe load of R410A to be replaced to an apparatus. The relative pressure(RDP_(R410A)) is represented by the ratio of the compressor dischargegas pressure (DP_(sample)) when the standard refrigerating cycle underthe above temperature conditions (T) is operated by using the workingfluid (sample) to the compressor discharge gas pressure (DP_(R410A))when the cycle is operated by using R410A, as shown in the followingformula (Z).

$\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{pressure}} \\\left( {RDP}_{R\; 410A} \right)\end{matrix} = \frac{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {DP}_{sample} \right)}{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu} R\; 410\; A\mspace{14mu}\left( {DP}_{R\; 410\; A} \right)}} & (Z)\end{matrix}$

As described above, the compressor discharge gas pressure means themaximum pressure in the standard refrigerating cycle under the abovetemperature conditions, and from the value, it is possible to estimatethe pressure load to an apparatus when a heat cycle system such as arefrigerating apparatus or an air-conditioning apparatus is practicallyoperated using the working fluid.

The working fluid according to an embodiment of the present inventionhas a relative pressure (RDP_(R410A)) of at most 1.100 as shown by(C-1). When the relative pressure (RDP_(R410A)) of the working fluidaccording to an embodiment is at most 1.100, the pressure load to anapparatus will hardly increase when a heat cycle system is operatedusing such a working fluid by using a predetermined apparatus underpredetermined conditions, as compared with a case where the heat cyclesystem is operated using R410A by using the same apparatus under thesame conditions. That is, when the condition (C-1) is satisfied, theworking fluid according to an embodiment can be basically used for anapparatus in which R410A has been used as the working fluid, without anyparticular change of design.

The relative pressure (RDP_(R410A)) of the working fluid according to anembodiment is preferably at most 1.000. The lower limit of the relativepressure (RDP_(R410A)) of the working fluid according to an embodimentis not particularly limited.

(D) Combustion Lower Limit

The combustion lower limit is the lower limit of the combustion rangei.e. the range of the volume concentration (%) of the working fluidbased on the entire amount of the working fluid and the air, withinwhich the working fluid mixed with the air can burn under thepredetermined conditions. In the present invention, the combustion rangeis the combustion range measured in accordance with method A in HighPressure Gas Safety Act.

“Measured in accordance with method A in High Pressure Gas Safety Act”includes measurement by method A in High Pressure Gas Safety Act andincludes measurement by a measurement method other than method A, forexample, by a measurement method modified to such an extent that themodification is acceptable as an alternative to the method A.

In a case where the working fluid consists of a single compound, thecombustion lower limit may be literature data by the above-exemplifiedmeasurement method. Further, in a case where the working fluid is amixture, the combustion lower limit may be actually measured by theabove-exemplified measurement method, or may be calculated as a weightedaverage by the molar composition employing the combustion lower limitsof the respective compounds constituting the working fluid.

The working fluid according to an embodiment of the present inventionhas a combustion lower limit of at least 5 vol % as represented by(D-1). When the combustion lower limit of the working fluid according toan embodiment is at least 5 vol %, that is, it satisfies the condition(D-1), even when the working fluid leaks out from a refrigerator or anair-conditioning apparatus, the working fluid is not highly flammablelike a hydrocarbon refrigerant such as propane, butane or isobutane in anormal environment, and such a situation can be handled withpredetermined measures.

The combustion lower limit of the working fluid according to anembodiment is preferably at least 7%, more preferably at least 10%.Particularly, the working fluid according to an embodiment has nocombustion range. In a case where the working fluid according to anembodiment has a combustion range, the upper limit is not particularlylimited. However, in order that the working fluid will not be aflammable gas in High Pressure Gas Safety Act, it is preferred that thecombustion lower limit is at least 10% and the difference between theupper limit and the lower limit of the combustion range is at least 20%.

(E) Self-Decomposition Property

The working fluid according to an embodiment of the present inventionhas no self-decomposition property. That is, of the working fluidaccording to an embodiment, the pressure will not exceed 2.00 MPaG in acombustion test by equipment in accordance with method A for measurementof the combustion range in High Pressure Gas Safety Act under conditionsof 0.98 MPaG and 250° C., as defined by (E-1). That is, the workingfluid has a property such that the temperature and the pressure are notsubstantially changed by the combustion test.

By the working fluid according to an embodiment satisfying the condition(E-1), in a heat cycle system such as a refrigerating apparatus or anair-conditioning apparatus, the working fluid can be stably usedcontinuously without any particularly measurements for a long period oftime.

The self-decomposition property (E) of the working fluid in the presentinvention is evaluated specifically as follows using equipment inaccordance with method A recommended as equipment for measurement of thecombustion range of a gas mixture containing halogen, by individualnotifications in High Pressure Gas Safety Act.

A sample (working fluid) is enclosed in a spherical pressure resistantreactor having an internal capacity of 650 cm³ and having a temperaturein the interior controlled at a predetermined temperature (250° C.) fromthe outside, to a predetermined pressure (0.98 MPa by the gaugepressure), and a platinum wire placed in the interior of the reactor isfused to apply an about 30 J energy. The temperature and pressurechanges in the pressure resistant reactor generated after applicationare measured to confirm whether the self-decomposition reaction occurredor not.

In a case where remarkable pressure increase and temperature increaseare confirmed after application as compared with before application, thesample (working fluid) is rated as having undergone self-decompositionreaction, that is, as having self-decom position property. On thecontrary, in a case where remarkable pressure and temperature increasesare not confirmed after application, the sample (working fluid) is ratedas not having undergone self-decomposition reaction, that is, as havingno self-decom position property.

Further, in the present invention, “there is no remarkable pressureincrease from the initial pressure of 0.98 MPaG” means that the pressureafter application is within a range of from 0.98 MPaG to 2.00 MPa.Further, “there is no temperature increase from the initial temperatureof 250° C.” means that the temperature after application is within arange of from 250° C. to 260° C.

The above-described properties of the working fluid according to anembodiment of the present invention are summarized in the followingTable 1. In Table 1, the rows represent the physical properties (A) to(E) to be evaluated, and the columns represent physical property values(1) to (4). In Table 1, with respect to the physical properties (A) to(E), the columns (1), (2), (3) and (4) respectively represent anessential requirement, a preferred range, a more preferred range and aparticularly preferred range. In Table 1, the range (less than 300) ofthe column (1) of the row (A) GWP corresponds to the requirement of theabove (A-1). Likewise, the ranges of the column (1) of the rows (B) to(E) in Table 1 correspond to the requirements (B-1) to (E-1).

TABLE 1 Physical properties/conditions (1) (2) (3) (4) (A) GWP <300 ≤250≤200 ≤150 (B) Relative cycle performance ≥0.820 ≥0.900 ≥0.950 ≥1.000(relative to R410A) (C) Relative pressure (RDP_(R410A)) ≤1.100 ≤1.000≤0.900 ≤0.820 (D) Combustion lower limit [vol %] ≥5 ≥7 ≥10 No combustionrange (E) Self-decomposition property Nil

The working fluid according to an embodiment of the present invention isrequired to satisfy the conditions (A)-(1), (B)-(1), (C)-(1), (D)-(1)and (E)-(1) in Table 1. So long as the above conditions are satisfied,the combination of the rows (A) to (E) and the respective levels (2) to(4) is not particularly limited. Most preferred is a working fluid whichsatisfies all the conditions (A)-(4), (B)-(4), (C)-(2), (D)-(4) and(E)-(1).

As the heat cycle system to which the working fluid for heat cycle ofthe present invention is applied, a heat cycle system by heat exchangerssuch as a condenser and an evaporator may be used without anyparticularly restriction. The heat cycle system, for example, arefrigerating cycle, has a mechanism in which a gaseous working fluid iscompressed by a compressor and cooled by a condenser to form a highpressure liquid, the pressure of the liquid is lowered by an expansionvalve, and the liquid is vaporized at low temperature by an evaporatorso that heat is removed by the heat of vaporization.

<Composition of Working Fluid>

The composition of the working fluid for heat cycle of the presentinvention is not particularly limited so long as all the conditions(A-1) to (E-1) are satisfied. The working fluid may consist of a singlecompound or may be a mixture. However, no composition which satisfiesall the conditions (A-1) to (E-1) by itself has been known. Accordingly,to obtain a working fluid according to an embodiment which satisfies allthe conditions (A-1) to (E-1), for example, a method of selecting thecombination of compounds constituting the working fluid and adjustingthe contents of the selected compounds so as to satisfy the conditions(A-1) to (E-1) as follows, may be mentioned.

The combination of compounds which may constitute the working fluid ofthe present invention, in order to satisfy the condition (A-1),preferred is a combination of compounds including at least one HFO (aHFC having a carbon-carbon double bond) which intrinsically has a lowGWP and which satisfies the condition (A-1) by itself.

The HFO may, for example, be HFO-1123, HFO-1132(Z) which iscis-HFO-1132, HFO-1132(E) which is trans-HFO-1132,2,3,3,3-tetrafluoropropene (HFO-1234yf), 2-fluoropropene (HFO-1261yf),1,1,2-trifluoropropene (HFO-1243yc), trans-1,2,3,3,3-pentafluoropropene(HFO-1225ye(E)), cis-1,2,3,3,3-pentafluoropropene (HFO-1225ye(Z)),trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)),cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)) or 3,3,3-trifluoropropene(HFO-1243zf).

Preferably, among such HFOs, a compound having a high relative cycleperformance, for example, a compound which satisfies the condition (B-1)or a compound which may satisfy the condition of (B-1) by combinationwith another compound, is selected. Such a compound may, for example, beHFO-1123, HFO-1132(Z) or HFO-1232(E).

Further, GWP of HFO-1123 is 0.3 as a value measured in accordance withIntergovernmental Panel on Climate Change (IPCC), Fourth assessmentreport. Further, GWPs of HFO-1132(Z) and HFO-1132(E) are not disclosedin IPCC, Fourth assessment report, and can be estimated to be at most10, from GWP of other HFOs, for example, GWP of 6 of HFO-1234ze(E) andHFO-1234ze(Z) and GWP of 4 of HFO-1234yf.

In Table 2, physical property values for (A) to (E) of HFO-1123,HFO-1132(Z) and HFO-1132(E) together with the conditions (A-1) to (E-1)which the working fluid according to an embodiment should satisfy.Further, physical property values for (A) to (E) of R410A which is to bereplaced by the working fluid according to an embodiment are also shown.

TABLE 2 Relative cycle performance Relative Combustion Self- (relativeto pressure lower limit decomposition Compound GWP R410A) (RDP_(R410A))(vol %) property Working fluid <300 ≥0.820 ≤1.100 ≥5   Nil R410A 20881.000 1.000 No Nil combustion range HFO-1123 0.3 1.056 1.242   6.3¹⁾Observed HFO-1132(E) ≤10 0.917 0.834 4¹⁾ Observed HFO-1132(Z) ≤10 0.5150.409 4¹⁾ Observed

From Table 2, physical properties of HFO-1123, HFO-1132(Z) andHFO-1132(E) which are not satisfied as the working fluid according to anembodiment are known. Considering such physical properties, HFO-1123,HFO-1132(Z) and HFO-1132(E) are combined with a compound so as toachieve physical properties which have not been satisfied as the workingfluid according to an embodiment while physical properties which havealready been satisfied are kept so as not to be out of the ranges of theworking fluid according to an embodiment. Such a compound may, forexample, be a HFO other than HFO-1123, HFO-1132(Z) and HFO-1132(E), anda HFC.

The HFO to be combined with HFO-1123, HFO-1132(Z), HFO-1132(E) and thelike, is preferably a HFO which has a relative cycle performance at acertain level or higher, which has a low relative pressure(RDP_(R410A)), and which has no self-decomposition property.Specifically, it may, for example, be HFO-1234ze(E), HFO-1234ze(Z) orHFO-1234yf.

The HFC is preferably properly selected with a view to keepingparticularly GWP within the range (A-1) and the relative cycleperformance within the range (B-1) of a mixture with the above HFO as aworking fluid.

The HFC may, for example, be HFC-32, difluoroethane, trifluoroethane,tetrafluoroethane, pentafluoroethane (HFC-125), pentafluoropropane,hexafluoropropane, heptafluoropropane, pentafluorobutane orheptafluorocyclopentane. From the above viewpoint, preferred is HFC-32,1,1-difluoroethane (HFC-152a), 1,1,2,2-tetrafluoroethane (HFC-134) or1,1,1,2-tetrafluoroethane (HFC-134a).

The HFC to be combined with the above HFO-1123, HFO-1132(Z), HFO-1132(E)and the like, is preferably a HFC which has a relatively low GWP, forexample, at most 1,500, which has a high relative cycle performanceand/or a low relative pressure (RDP_(R410A)), and which has noself-decomposition property. It may, for example, be specifically HFC-32or HFC-134a, and is particularly preferably HFC-32.

In Table 3, physical property values for (A) to (E) of HFO-1234ze(E),HFO-1234yf, HFC-32 and HFC-134a are shown together with (A-1) to (E-1)which the working fluid according to an embodiment should satisfy.Further, physical property values for (A) to (E) of R410A which is to bereplaced by the working fluid according to an embodiment are also shown.

TABLE 3 Relative cycle performance Relative Combustion Self- (relativeto pressure lower limit decomposition Compound GWP R410A) (RDP_(R410A))(vol %) property Working fluid <300 ≥0.820 ≤1.100 ≥5    Nil R410A 20881.000 1.000 No Nil combustion range HFO-1234yf 4 0.441 0.427 6.3²⁾ NilHFO-1234ze(E) 6 0.364 0.327 7.0²⁾ Nil HFC-32 675 1.118 1.047 13.4¹⁾  NilHFC-134a 1430 0.481 0.427 No Nil combustion range

In Tables 2 and 3, in the column “combustion lower limit”, 1) representsa measured value measured in accordance with method A in High PressureGas Safety Act, and 2) represents a literature value measured inaccordance with method A in High Pressure Gas Safety Act.

Since HFO-1123, HFO-1132(Z) and HFO-1132(E) have self-decompositionproperty when used by themselves, the proportion of HFO-1123,HFO-1132(Z) or HFO-1132(E) based on the entire amount of the workingfluid is such that the working fluid has no self-decomposition property.

As a preferred combination of compounds for the working fluid accordingto an embodiment which satisfies (A-1) to (E-1), in a case whereHFO-1123 is used, the following combinations may be mentioned. In thefollowing description, mass % represents mass % based on 100 mass % ofthe entire working fluid.

(i-1) From 55 to 62 mass % of HFO-1123 and from 38 to 45 mass % ofHFO-1234yf.

(i-2) From 10 to 70 mass % of HFO-1123, from 10 to 50 mass % ofHFO-1234yf and from 10 to 40 mass % of HFC-32.

(i-3) From 20 to 50 mass % of HFO-1123, from 20 to 40 mass % ofHFO-1234ze(E) and from 10 to 40 mass % of HFC-32.

So long as (A-1) to (E-1) are satisfied, it is possible to combineHFO-1123, HFO-1234yf, HFO-1234ze(E) and HFC-32 in predeterminedproportions to obtain the working fluid of the present invention.Further, so long as (A-1) to (E-1) are satisfied, it is possible tocombine HFO-1123 with a HFO or HFC not used in the above (i-1) to (i-3)to obtain the working fluid of the present invention.

As a preferred combination of compounds for the working fluid accordingto an embodiment which satisfies (A-1) to (E-1), in a case whereHFO-1132(Z) is used, the following combinations may be mentioned. In thefollowing description, mass % represents mass % based on 100 mass % ofthe entire working fluid.

(ii-1) From 60 to 70 mass % of HFO-1132(Z) and from 30 to 40 mass % ofHFC-32.

(ii-2) From 20 to 40 mass % of HFO-1132(Z), from 20 to 40 mass % ofHFO-1234yf and from 40 to 44 mass % of HFC-32.

So long as (A-1) to (E-1) are satisfied, it is possible to combineHFO-1132(Z) with a HFO or HFC not used in the above (ii-1) or (ii-2) toobtain the working fluid of the present invention.

As a preferred combination of compounds for the working fluid accordingto an embodiment which satisfied (A-1) to (E-1), in a case whereHFO-1132(E) is used, the following combinations may be mentioned. In thefollowing description, mass % represents mass % based on 100 mass % ofthe entire working fluid.

(iii-1) From 60 to 70 mass % of HFO-1132(E) and from 30 to 40 mass % ofHFC-32.

(iii-2) From 20 to 70 mass % of HFO-1132(E), from 10 to 40 mass % ofHFO-1234yf and from 20 to 40 mass % of HFC-32.

So long as (A-1) to (E-1) are satisfied, it is possible to combineHFO-1132(E) with a HFO or HFC not used in the above (iii-1) to (iii-3)to obtain the working fluid of the present invention.

Further, so long as (A-1) to (E-1) are satisfied, it is possible tocombine the above-exemplified mixture of HFO-1123, HFO-1132(Z) orHFO-1132(E) and another HFO or HFC, with still another HFO or HFC.

(Other Component)

The working fluid according to an embodiment may contain, other than theHFO or the HFC, e.g. another component which is vaporized and liquefiedtogether with the HFO or the HFC, as the case requires, so long as (A-1)to (E-1) are satisfied.

Such a component other than the HFO or the HFC (hereinafter referred toas other component) may, for example, be carbon dioxide, a hydrocarbon,a chlorofluoroolefin (CFO), or a hydrochlorofluoroolefin (HCFO). Suchanother component is preferably a component which has less influenceover the ozone layer and which has less influence over global warming.

The hydrocarbon may, for example, be propane, propylene, cyclopropane,butane, isobutane, pentane or isopentane. The hydrocarbon may be usedalone or in combination of two or more.

In a case where the working fluid contains a hydrocarbon, its content isless than 10 mass %, preferably from 1 to 5 mass %, more preferably from3 to 5 mass % per 100 mass % of the working fluid. When the content ofthe hydrocarbon is at least the lower limit, the solubility of a mineralrefrigerant oil in the working fluid will be favorable.

The CFO may, for example, be chlorofluoropropene orchlorofluoroethylene. With a view to suppressing flammability of theworking fluid without significantly decreasing the cycle performance ofthe working fluid, the CFO is preferably1,1-dichloro-2,3,3,3-tetrafluoropropene (CFO-1214ya),1,3-dichloro-1,2,3,3-tetrafluoropropene (CFO-1214yb) or1,2-dichloro-1,2-difluoroethylene (CFO-1112).

The CFO may be used alone or in combination of two or more.

In a case where the working fluid contains the CFO, its content is lessthan 10 mass %, preferably from 1 to 8 mass %, more preferably from 2 to5 mass % per 100 mass % of the working fluid. When the content of theCFO is at least the lower limit, the flammability of the working fluidtends to be suppressed. When the content of the CFO is at most the upperlimit, favorable cycle performance is likely to be obtained.

The HCFO may, for example, be hydrochlorofluoropropene orhydrochlorofluoroethylene. With a view to suppressing the flammabilityof the working fluid without significantly decreasing the cycleperformance of the working fluid, the HCFO is preferably1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd) or1-chloro-1,2-difluoroethylene (HCFO-1122). The HCFO may be used alone orin combination of two or more.

In a case where the working fluid contains the HCFO, the content of theHCFO per 100 mass % of the working fluid is less than 10 mass %,preferably from 1 to 8 mass %, more preferably from 2 to 5 mass %. Whenthe content of the HCFO is at least the lower limit, the flammability ofthe working fluid tends to be suppressed. When the content of the HCFOis at most the upper limit, favorable cycle performance is likely to beobtained.

In a case where the working fluid used for the composition for a heatcycle system of the present invention contains the above anothercomponent, the total content of such another component in the workingfluid is less than 10 mass %, preferably at most 8 mass %, morepreferably at most 5 mass % per 100 mass % of the working fluid.

[Composition for Heat Cycle System]

The working fluid of the present invention may be used, in applicationto a heat cycle system, as the composition for a heat cycle system ofthe present invention usually as mixed with a refrigerant oil. Thecomposition for a heat cycle system of the present invention comprisingthe working fluid of the present invention and a refrigerant oil mayfurther contain known additives such as a stabilizer and a leakdetecting substance.

<Refrigerant Oil>

As a refrigerant oil, a known refrigerant oil which has been used for acomposition for a heat cycle system together with a working fluidcomprising a halogenated hydrocarbon may be used without any particularrestrictions. The refrigerant oil may, for example, be specifically anoxygen-containing synthetic oil (such as an ester refrigerant oil or anether refrigerant oil), a fluorinated refrigerant oil, a mineralrefrigerant oil or a hydrocarbon synthetic oil.

The ester refrigerant oil may, for example, be a dibasic acid ester oil,a polyol ester oil, a complex ester oil or a polyol carbonate oil.

The dibasic acid ester oil is preferably an ester of a C₅₋₁₀ dibasicacid (such as glutaric acid, adipic acid, pimelic acid, suberic acid,azelaic acid or sebacic acid) with a C₁₋₁₅ monohydric alcohol which islinear or has a branched alkyl group (such as methanol, ethanol,propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol,decanol, undecanol, dodecanol, tridecanol, tetradecanol orpentadecanol). Specifically, ditridecyl glutarate, di(2-ethylhexyl)adipate, diisodecyl adipate, ditridecyl adipate or di(3-ethylhexyl)sebacate may, for example, be mentioned.

The polyol ester oil is preferably an ester of a diol (such as ethyleneglycol, 1,3-propanediol, propylene glycol, 1,4-butanediol,1,2-butandiol, 1,5-pentadiol, neopentyl glycol, 1,7-heptanediol or1,12-dodecanediol) or a polyol having from 3 to 20 hydroxy groups (suchas trimethylolethane, trimethylolpropane, trimethylolbutane,pentaerythritol, glycerin, sorbitol, sorbitan or a sorbitol/glycerincondensate) with a C₆₋₂₀ fatty acid (such as a linear or branched fattyacid such as hexanoic acid, heptanoic acid, octanoic acid, nonanoicacid, decanoic acid, undecanoic acid, dodecanoic acid, eicosanoic acidor oleic acid, or a so-called neo acid having a quaternary a carbonatom).

The polyol ester oil may have a free hydroxy group.

The polyol ester oil is preferably an ester (such as trimethylolpropanetripelargonate, pentaerythritol 2-ethylhexanoate or pentaerythritoltetrapelargonate) of a hindered alcohol (such as neopentyl glycol,trimethylolethane, trimethylolpropane, trimethylolbutane orpentaerythritol).

The complex ester oil is an ester of a fatty acid and a dibasic acid,with a monohydric alcohol and a polyol. The fatty acid, the dibasicacid, the monohydric alcohol and the polyol may be as defined above.

The polyol carbonate oil is an ester of carbonic acid with a polyol.

The polyol may be the above-described diol or the above-describedpolyol. Further, the polyol carbonate oil may be a ring-opening polymerof a cyclic alkylene carbonate.

The ether refrigerant oil may be a polyvinyl ether oil or apolyoxyalkylene oil.

The polyvinyl ether oil may be one obtained by polymerizing a vinylether monomer such as an alkyl vinyl ether, or a copolymer obtained bycopolymerizing a vinyl ether monomer and a hydrocarbon monomer having anolefinic double bond.

The vinyl ether monomer may be used alone or in combination of two ormore.

The hydrocarbon monomer having an olefinic double bond may, for example,be ethylene, propylene, various forms of butene, various forms ofpentene, various forms of hexene, various forms of heptene, variousforms of octene, diisobutylene, triisobutylene, styrene, α-methylstyreneor alkyl-substituted styrene. The hydrocarbon monomer having an olefinicdouble bond may be used alone or in combination of two or more.

The polyvinyl ether copolymer may be either of a block copolymer and arandom copolymer. The polyvinyl ether oil may be used alone or incombination of two or more.

The polyoxyalkylene oil may, for example, be a polyoxyalkylene monool, apolyoxyalkylene polyol, an alkyl ether of a polyoxyalkylene monool or apolyoxyalkylene polyol, or an ester of a polyoxyalkylene monool or apolyoxyalkylene polyol.

The polyoxyalkylene monool or the polyoxyalkylene polyol may be oneobtained by e.g. a method of subjecting a C₂₋₄ alkylene oxide (such asethylene oxide or propylene oxide) to ring-opening additionpolymerization to an initiator such as water or a hydroxygroup-containing compound in the presence of a catalyst such as analkali hydroxide. Further, one molecule of the polyoxyalkylene chain maycontain single oxyalkylene units or two or more types of oxyalkyleneunits. It is preferred that at least oxypropylene units are contained inone molecule.

The initiator to be used for the reaction may, for example, be water, amonohydric alcohol such as methanol or butanol, or a polyhydric alcoholsuch as ethylene glycol, propylene glycol, pentaerythritol or glycerol.

The polyoxyalkylene oil is preferably an alkyl ether or ester of apolyoxyalkylene monool or polyoxyalkylene polyol. Further, thepolyoxyalkylene polyol is preferably a polyoxyalkylene glycol.Particularly preferred is an alkyl ether of a polyoxyalkylene glycolhaving the terminal hydroxy group of the polyoxyalkylene glycol cappedwith an alkyl group such as a methyl group, which is called a polyglycoloil.

The fluorinated refrigerant oil may, for example, be a compound havinghydrogen atoms of a synthetic oil (such as the after-mentioned mineraloil, poly-α-olefin, alkylbenzene or alkylnaphthalene) substituted byfluorine atoms, a perfluoropolyether oil or a fluorinated silicone oil.

The mineral refrigerant oil may, for example, be a naphthene mineral oilor a paraffin mineral oil obtained by purifying a refrigerant oilfraction obtained by atmospheric distillation or vacuum distillation ofcrude oil by a purification treatment (such as solvent deasphalting,solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing,hydrotreating or clay treatment) optionally in combination.

The hydrocarbon synthetic oil may, for example, be a poly-α-olefin, analkylbenzene or an alkylnaphthalene.

The refrigerant oil may be used alone or in combination of two or more.

The refrigerant oil is preferably at least one member selected from apolyol ester oil, a polyvinyl ether oil and a polyglycol oil in view ofcompatibility with the working fluid.

The content of the refrigerant oil in the composition for a heat cyclesystem is not limited within a range not to remarkably decrease theeffects of the present invention, and is preferably from 10 to 100 partsby mass, more preferably from 20 to 50 parts by mass, per 100 parts bymass of the working fluid.

<Other Optional Component>

The stabilizer optionally contained in the composition for a heat cyclesystem is a component which improves the stability of the working fluidagainst heat and oxidation. As the stabilizer, a known stabilizer whichhas been used for a heat cycle system together with a working fluidcomprising a halogenated hydrocarbon, for example, an oxidationresistance-improving agent, a heat resistance-improving agent or a metaldeactivator, may be used without any particular restrictions.

The oxidation resistance-improving agent and the heatresistance-improving agent may, for example, beN,N′-diphenylphenylenediamine, p-octyldiphenylamine,p,p′-dioctyldiphenylamine, N-phenyl-1-naphthylamine,N-phenyl-2-naphthylamine, N-(p-dodecyl)phenyl-2-naphthylamine,di-1-naphthylamine, di-2-naphthylamine, N-alkylphenothiazine,6-(t-butyl)phenol, 2,6-di-(t-butyl)phenol,4-methyl-2,6-di-(t-butyl)phenol or4,4′-methylenebis(2,6-di-t-butylphenol). Each of the oxidationresistance-improving agent and the heat resistance-improving agent maybe used alone or in combination of two or more.

The metal deactivator may, for example, be imidazole, benzimidazole,2-mercaptobenzothiazole, 2,5-dimercaptothiadiazole,salicylidene-propylenediamine, pyrazole, benzotriazole, tritriazole,2-methylbenzamidazole, 3,5-dimethylpyrazole, methylenebis-benzotriazole,an organic acid or an ester thereof, a primary, secondary or tertiaryaliphatic amine, an amine salt of an organic acid or inorganic acid, aheterocyclic nitrogen-containing compound, an amine salt of an alkylphosphate, or a derivative thereof.

The content of the stabilizer in the composition for a heat cycle systemis not limited within a range not to remarkably decrease the effects ofthe present invention, and is preferably at most 5 parts by mass, morepreferably at most 1 part by mass per 100 parts by mass of the workingfluid.

The leak detecting substance optionally contained in the composition fora heat cycle system may, for example, be an ultraviolet fluorescent dye,an odor gas or an odor masking agent.

The ultraviolet fluorescent dye may be known ultraviolet fluorescentdyes which have been used for a heat cycle system together with aworking fluid comprising a halogenated hydrocarbon, such as dyes asdisclosed in e.g. U.S. Pat. No. 4,249,412, JP-A-10-502737,JP-A-2007-511645, JP-A-2008-500437 and JP-A-2008-531836.

The odor masking agent may be known perfumes which have been used for aheat cycle system together with a working fluid comprising a halogenatedhydrocarbon, such as perfumes as disclosed in e.g. JP-A-2008-500437 andJP-A-2008-531836.

In a case where the leak detecting substance is used, a solubilizingagent which improves the solubility of the leak detecting substance inthe working fluid may be used.

The solubilizing agent may be ones as disclosed in e.g.JP-A-2007-511645, JP-A-2008-500437 and JP-A-2008-531836.

The content of the leak detecting substance in the composition for aheat cycle system is not particularly limited within a range not toremarkably decrease the effects of the present invention, and ispreferably at most 2 parts by mass, more preferably at most 0.5 part bymass per 100 parts by mass of the working fluid.

[Heat Cycle System]

The heat cycle system of the present invention is a system employing thecomposition for a heat cycle system of the present invention. The heatcycle system of the present invention may be a heat pump systemutilizing heat obtained by a condenser or may be a refrigerating cyclesystem utilizing coldness obtained by an evaporator.

The heat cycle system of the present invention may, for example, bespecifically a refrigerator, an air-conditioning apparatus, a powergeneration system, a heat transfer apparatus and a secondary coolingmachine. Among them, the heat cycle system of the present invention,which stably and safely exhibits heat cycle performance in a workingenvironment at higher temperature, is preferably employed as anair-conditioning apparatus to be disposed outdoors in many cases.Further, the heat cycle system of the present invention is preferablyemployed also for a refrigerating apparatus.

The air-conditioning apparatus may, for example, be specifically a roomair-conditioner, a package air-conditioner (such as a store packageair-conditioner, a building package air-conditioner or a plant packageair-condition, a gas engine heat pump, a train air-conditioning systemor an automobile air-conditioning system.

The refrigerator may, for example, be specifically a showcase (such as abuilt-in showcase or a separate showcase), an industrial fridge freezer,a vending machine or an ice making machine.

The power generation system is preferably a power generation system byRankine cycle system.

The power generation system may, for example, be specifically a systemwherein in an evaporator, a working fluid is heated by e.g. geothermalenergy, solar heat or waste heat in a medium-to-high temperature rangeat a level of from 50 to 200° C., and the vaporized working fluid in ahigh temperature and high pressure state is adiabatically expanded by anexpansion device, so that a power generator is driven by the workgenerated by the adiabatic expansion to carry out power generation.

Further, the heat cycle system of the present invention may be a heattransport apparatus. The heat transport apparatus is preferably a latentheat transport apparatus.

The latent heat transport apparatus may, for example, be a heat pipeconducting latent heat transport utilizing evaporation, boiling,condensation, etc. of a working fluid filled in an apparatus, and atwo-phase closed thermosiphon. A heat pipe is applied to a relativelysmall-sized cooling apparatus such as a cooling apparatus of a heatingportion of a semiconductor device and electronic equipment. A two-phaseclosed thermosiphon is widely used for a gas/gas heat exchanger, toaccelerate snow melting and to prevent freezing of roads, since it doesnot require a wick and its structure is simple.

At the time of operation of the heat cycle system, in order to avoiddrawbacks due to inclusion of moisture or inclusion of non-condensinggas such as oxygen, it is preferred to provide a means to suppress suchinclusion.

If moisture is included in the heat cycle system, a problem may occurparticularly when the heat cycle system is used at low temperature. Forexample, problems such as freezing in a capillary tube, hydrolysis ofthe working fluid or the refrigerant oil, deterioration of materials byan acid component formed in the cycle, formation of contaminants, etc.may arise. Particularly, if the refrigerant oil is a polyglycol oil or apolyol ester oil, it has extremely high moisture absorbing propertiesand is likely to undergo hydrolysis, and inclusion of moisture decreasesproperties of the refrigerant oil and may be a great cause to impair thelong term reliability of a compressor. Accordingly, in order to suppresshydrolysis of the refrigerant oil, it is necessary to control themoisture concentration in the heat cycle system.

As a method of controlling the moisture concentration in the heat cyclesystem, a method of using a moisture-removing means such as adesiccating agent (such as silica gel, activated aluminum or zeolite)may be mentioned. The desiccating agent is preferably brought intocontact with the composition for a heat cycle system in a liquid state,in view of the dehydration efficiency. For example, the desiccatingagent is located at the outlet of the condenser 12 or at the inlet ofthe evaporator 14 to be brought into contact with the composition for aheat cycle system.

The desiccating agent is preferably a zeolite desiccating agent in viewof chemical reactivity of the desiccating agent and the composition fora heat cycle system, and the moisture absorption capacity of thedesiccating agent.

The zeolite desiccating agent is, in a case where a refrigerant oilhaving a large moisture absorption as compared with a conventionalmineral refrigerant oil is used, preferably a zeolite desiccating agentcontaining a compound represented by the following formula (3) as themain component in view of excellent moisture absorption capacity.M_(2/n)O.Al₂O₃ .xSiO₂ .yH₂O  (3)wherein M is a group 1 element such as Na or K or a group 2 element suchas Ca, n is the valence of M, and x and y are values determined by thecrystal structure. The pore size can be adjusted by changing M.

To select the desiccating agent, the pore size and the fracture strengthare important.

In a case where a desiccating agent having a pore size larger than themolecular size of the working fluid contained in the composition for aheat cycle system is used, the working fluid is adsorbed in thedesiccating agent and as a result, chemical reaction between the workingfluid and the desiccating agent will occur, thus leading to undesiredphenomena such as formation of non-condensing gas, a decrease in thestrength of the desiccating agent, and a decrease in the adsorptioncapacity.

Accordingly, it is preferred to use as the desiccating agent a zeolitedesiccating agent having a small pore size. Particularly preferred issodium/potassium type A synthetic zeolite having a pore size of at most3.5 Å. By using a sodium/potassium type A synthetic zeolite having apore size smaller than the molecular size of the working fluid, it ispossible to selectively adsorb and remove only moisture in the heatcycle system without adsorbing the working fluid. In other words, theworking fluid is less likely to be adsorbed in the desiccating agent,whereby heat decomposition is less likely to occur and as a result,deterioration of materials constituting the heat cycle system andformation of contaminants can be suppressed.

The size of the zeolite desiccating agent is preferably from about 0.5to about 5 mm, since if it is too small, a valve or a thin portion inpipelines of the heat cycle system may be clogged, and if it is toolarge, the drying capacity will be decreased. Its shape is preferablygranular or cylindrical.

The zeolite desiccating agent may be formed into an optional shape bysolidifying powdery zeolite by a binding agent (such as bentonite). Solong as the desiccating agent is composed mainly of the zeolitedesiccating agent, other desiccating agent (such as silica gel oractivated alumina) may be used in combination.

The proportion of the zeolite desiccating agent based on the compositionfor a heat cycle system is not particularly limited.

If non-condensing gas is included in the heat cycle system, it hasadverse effects such as heat transfer failure in the condenser or theevaporator and an increase in the working pressure, and it is necessaryto suppress its inclusion as far as possible. Particularly, oxygen whichis one of non-condensing gases reacts with the working fluid or therefrigerant oil and promotes their decomposition.

The non-condensing gas concentration is preferably at most 1.5 vol %,particularly preferably at most 0.5 vol % by the volume ratio based onthe working fluid, in a gaseous phase of the working fluid.

According to the above-described heat cycle system of the presentinvention, which employs the working fluid of the present inventionhaving high safety, practically sufficient heat cycle performance can beobtained while suppressing influence over global warming, and there issubstantially no problem with respect to the temperature glide.

EXAMPLES

Now, the present invention will be described in further detail withreference to Examples. However, it should be understood that the presentinvention is by no means restricted to specific Examples.

In the following Examples of the present invention and ComparativeExamples, GWP and the combustion lower limit were obtained bycalculation using values of the respective compounds by themselvesrespectively in accordance with the above methods. As the values of therespective compounds by themselves, values in the above Tables 2 and 3and the following Table 4 were employed.

TABLE 4 Combustion range Combustion lower limit Compound GWP (vol %)Reference source HFO-1243zf 9 4.7 Known value by method A HCFO-1122 <1013 Measured value by method A HCFO-1224yd <10 No Measured value bymethod A combustion range Propane 3 2.1 Known value by method A Butane8.4 1.8 Known value by method A Isobutane 8.4 1.8 Known value by methodA

Examples 1 to 22

In Examples 1 to 22, a working fluid having HFO-1123 and at least onemember of HFO-1234yf, HFC-32 and HFO-1234ze(E) mixed in a proportion asidentified in Tables 5 to 7 was prepared, and by the above methods, (A)GWP, (B) relative cycle performance (relative to R410A), (C) relativepressure (RDP_(R410A)), (D) combustion lower limit and (E)self-decomposition property were measured, calculated and evaluated. Theresults are shown in Tables 5 to 7.

TABLE 5 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1123 HFO-1234yfGWP performance pressure limit (vol %) property 1 60 40 2 0.845 0.9346.3 Nil

TABLE 6 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1123 HFO-1234yfHFC-32 GWP performance pressure limit (vol %) property 2 60 30 10 690.924 1.018 6.9 Nil 3 50 40 10 69 0.870 0.933 6.9 Nil 4 70 10 20 1361.056 1.178 7.4 Nil 5 50 30 20 136 0.944 1.010 7.5 Nil 6 40 40 20 1370.889 0.925 7.6 Nil 7 30 50 20 137 0.832 0.841 7.6 Nil 8 40 30 30 2040.959 0.996 8.2 Nil 9 30 40 30 204 0.902 0.912 8.2 Nil 10 20 50 30 2050.842 0.829 8.3 Nil 11 40 20 40 271 1.025 1.061 8.8 Nil 12 30 30 40 2710.968 0.978 8.9 Nil 13 20 40 40 272 0.909 0.894 9.0 Nil 14 10 50 40 2720.846 0.812 9.1 Nil

TABLE 7 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1123HFO-1234ze(E) HFC-32 GWP performance pressure limit (vol %) property 1550 40 10 70 0.832 0.842 7.1 Nil 16 50 30 20 137 0.909 0.940 7.7 Nil 1740 40 20 138 0.849 0.845 7.8 Nil 18 40 30 30 204 0.923 0.934 8.4 Nil 1930 40 30 205 0.861 0.840 8.6 Nil 20 40 20 40 271 0.996 1.020 9.0 Nil 2130 30 40 272 0.931 0.923 9.1 Nil 22 20 40 40 272 0.867 0.831 9.3 Nil

Examples 23 to 26

In Examples 23 to 26, a working fluid having HFO-1132(Z) and at leastone of HFO-1234yf and HFC-32 mixed in a proportion as identified inTables 8 and 9 was prepared, and by the above methods, (A) GWP, (B)relative cycle performance (relative to R410A), (C) relative pressure(RDP_(R410A)), (D) combustion lower limit and (E) self-decompositionproperty were measured, calculated and evaluated. The results are shownin Tables 8 and 9.

TABLE 8 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1132(Z) HFC-32GWP performance pressure limit (vol %) property 23 70 30 210 1.041 1.0105.3 Nil 24 60 40 276 1.072 1.048 5.8 Nil

TABLE 9 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1132(Z) HFC-32HFO-1234yf GWP performance pressure limit (vol %) property 25 20 40 40274 0.820 0.869 7.5 Nil 26 40 40 20 275 0.827 0.976 6.5 Nil

Examples 27 to 34

In Examples 27 to 34, a working fluid having HFO-1132(E) and at leastone of HFO-1234yf and HFC-32 mixed in a proportion as identified inTables 10 and 11 was prepared, and by the above methods, (A) GWP, (B)relative cycle performance (relative to R410A), (C) relative pressure(RDP_(R410A)), (D) combustion lower limit and (E) self-decompositionproperty were measured, calculated and evaluated. The results are shownin Tables 10 and 11.

TABLE 10 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1132(E) HFC-32GWP performance pressure limit (vol %) property 27 70 30 210 1.041 0.6335.3 Nil 28 60 40 276 1.072 0.703 5.8 Nil

TABLE 11 Properties Working fluid composition [mass %] Relative cycleRelative Combustion lower Self-decomposition Example HFO-1132(E) HFC-32HFO-1234yf GWP performance pressure limit (vol %) property 29 20 40 40274 0.896 0.753 7.5 Nil 30 40 20 40 141 0.858 0.620 5.7 Nil 31 40 40 20275 0.992 0.738 6.5 Nil 32 60 20 20 142 0.945 0.595 5.1 Nil 33 60 30 10209 1.011 0.651 5.5 Nil 34 70 20 10 142 0.979 0.579 5.0 Nil

Comparative Examples 1 to 54

In Comparative Examples 1 to 54, a working fluid having at least oneHFO, and at least one of another HFO, a HFC, a hydrocarbon and a HCFOmixed in a proportion as identified in Tables 12 to 20, was prepared,and by the above methods, (A) GWP, (B) relative cycle performance(relative to R410A), (C) relative pressure (RDP_(R410A)), (D) combustionlower limit and (E) self-decomposition property were measured,calculated and evaluated. The results are shown in Tables 12 to 20.

TABLE 12 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 HFC-32 GWP performance pressure limit (vol %) property 1 90 1068 1.085 1.256 6.8 Observed 2 80 20 135 1.109 1.256 7.4 Observed 3 70 30203 1.128 1.246 8.0 Nil 4 60 40 270 1.141 1.227 8.6 Nil 5 50 50 3381.148 1.204 9.3 Nil 6 40 60 405 1.150 1.176 10.0 Nil 7 30 70 473 1.1471.146 10.8 Nil 8 20 80 540 1.141 1.114 11.6 Nil 9 10 90 608 1.131 1.08112.5 Nil

TABLE 13 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 HFO-1234ze(E) GWP performance pressure limit (vol %) property10 90 10 1 0.992 1.138 6.3 Observed 11 80 20 1 0.927 1.033 6.4 Observed12 70 30 2 0.866 0.93 6.5 Observed 13 60 40 3 0.808 0.832 6.5 Nil 14 5050 3 0.750 0.739 6.6 Nil 15 40 60 4 0.685 0.653 6.6 Nil 16 30 70 4 0.6110.570 6.7 Nil 17 20 80 5 0.529 0.490 6.8 Nil 18 10 90 5 0.443 0.410 6.9Nil 19 8 92 6 0.427 0.394 6.9 Nil 20 6 94 6 0.410 0.377 6.9 Nil 21 4 966 0.394 0.361 7.0 Nil 22 2 98 6 0.379 0.344 7.0 Nil

TABLE 14 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1234yf HFC-32 GWP performance pressure limit (vol %) property 23 9010 71 0.538 0.513 6.8 Nil 24 80 20 138 0.628 0.591 7.4 Nil 25 70 30 2050.708 0.663 8.0 Nil 26 60 40 272 0.780 0.730 8.6 Nil 27 50 50 340 0.8460.792 9.3 Nil 28 40 60 407 0.907 0.851 10.0 Nil 29 30 70 474 0.965 0.90510.8 Nil 30 20 80 541 1.020 0.956 11.6 Nil 31 10 90 608 1.071 1.003 12.5Nil

TABLE 15 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1234ze(E) HFC-32 GWP performance pressure limit (vol %) property 3298 2 19 0.384 0.347 7.1 Nil 33 96 4 33 0.406 0.366 7.3 Nil 34 94 6 460.427 0.385 7.4 Nil 35 92 8 60 0.448 0.403 7.6 Nil 36 90 10 73 0.4690.421 7.7 Nil 37 80 20 140 0.568 0.506 8.4 Nil 38 70 30 207 0.655 0.5859.1 Nil 39 60 40 274 0.732 0.660 9.8 Nil 40 50 50 341 0.801 0.732 10.4Nil 41 40 60 407 0.867 0.801 11.0 Nil 42 30 70 474 0.931 0.868 11.7 Nil43 20 80 541 0.995 0.931 12.3 Nil 44 10 90 608 1.059 0.991 12.8 Nil

TABLE 16 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 Propane GWP performance pressure limit (vol %) property 45 9010 0 0.854 1.154 5.58 Observed 46 80 20 0 0.824 1.059 4.97 Nil

TABLE 17 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 Butane GWP performance pressure limit (vol %) property 47 80 200 0.648 0.749 5.12 Observed 48 60 40 0 0.462 0.510 4.12 Nil

TABLE 18 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 Isobutane GWP performance pressure limit (vol %) property 49 8020 0 0.696 0.846 5.12 Observed 50 60 40 0 0.572 0.599 4.12 Nil

TABLE 19 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 HFO-1243zf GWP performance pressure limit (vol %) property 5180 20 0 0.696 1.097 6.02 Observed 52 60 40 0 0.729 0.921 5.72 Nil

TABLE 20 Properties Comparative Working fluid composition [mass %]Relative cycle Relative Combustion lower Self-decomposition ExampleHFO-1123 HFO-1122 GWP performance pressure limit (vol %) property 53 6020 0 0.639 0.744 7.7 Observed 54 40 40 0 0.525 0.561 8.8 Nil

INDUSTRIAL APPLICABILITY

The composition for a heat cycle system of the present invention and theheat cycle system using the composition, are useful for a refrigerator(such as a built-in showcase, a separate showcase, an industrial fridgefreezer, a vending machine or an ice making machine), anair-conditioning apparatus (such as a room air-conditioner, a storepackage air-conditioner, a building package air-conditioner, a plantpackage air-conditioner, a gas engine heat pump, a trainair-conditioning system or an automobile air-conditioning system), powergeneration system (such as exhaust heat recovery power generation) or aheat transport apparatus (such as a heat pipe).

This application is a continuation of PCT Application No.PCT/JP2015/051409, filed on Jan. 20, 2015, which is based upon andclaims the benefit of priorities from Japanese Patent Application No.2014-017031 filed on Jan. 31, 2014, Japanese Patent Application No.2014-017967 filed on Jan. 31, 2014, Japanese Patent Application No.2014-030856 filed on Feb. 20, 2014, Japanese Patent Application No.2014-030857 filed on Feb. 20, 2014, Japanese Patent Application No.2014-033345 filed on Feb. 24, 2014, Japanese Patent Application No.2014-053765 filed on Mar. 17, 2014, Japanese Patent Application No.2014-055603 filed on Mar. 18, 2014, Japanese Patent Application No.2014-118163 filed on Jun. 6, 2014, Japanese Patent Application No.2014-118164 filed on Jun. 6, 2014, Japanese Patent Application No.2014-118165 filed on Jun. 6, 2014, Japanese Patent Application No.2014-118166 filed on Jun. 6, 2014, Japanese Patent Application No.2014-118167 filed on Jun. 6, 2014, Japanese Patent Application No.2014-127744 filed on Jun. 20, 2014, Japanese Patent Application No.2014-127745 filed on Jun. 20, 2014, Japanese Patent Application No.2014-148347 filed on Jul. 18, 2014, Japanese Patent Application No.2014-148348 filed on Jul. 18, 2014, Japanese Patent Application No.2014-148350 filed on Jul. 18, 2014, Japanese Patent Application No.2014-187002 filed on Sep. 12, 2014, Japanese Patent Application No.2014-187003 filed on Sep. 12, 2014, Japanese Patent Application No.2014-187004 filed on Sep. 12, 2014, Japanese Patent Application No.2014-187005 filed on Sep. 12, 2014 and Japanese Patent Application No.2014-187006 filed on Sep. 12, 2014. The contents of those applicationsare incorporated herein by reference in their entireties.

REFERENCE SYMBOLS

10: Refrigerating cycle system, 11: compressor, 12: condenser, 13:expansion valve, 14: evaporator, 15, 16: pump.

What is claimed is:
 1. A working fluid for heat cycle, the working fluidcomprising: 1,1,2-trifluoroethylene (HFO-1123); and at least oneselected from the group consisting of trans-1,3,3,3,-tetrafluoropropene(HFO-1234ze(E)), cis-1,3,3,3,-tetrafluoropropene (HFO-1234ze(Z)),2,3,3,3-tetrafluoropropene (HFO-1234yf), and difluoromethane (HFC-32),wherein the working fluid satisfies the following properties (A-1) to(E-1): (A-1): the global warming potential (100 years) inIntergovernmental Panel on Climate Change (IPCC), Fourth assessmentreport, is at most 200; (B-1): the product of the relative refrigeratingcapacity (RQ_(R410A)) calculated in accordance with the followingformula (X) and the relative coefficient of performance (RCOP_(R410A))calculated in accordance with the following formula (Y) is at least0.820: $\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{refrigerating}} \\{{capacity}\mspace{14mu}\left( {RQ}_{R\; 410\; A} \right)}\end{matrix} = \frac{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( Q_{sample} \right)}{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu} R\; 410A\mspace{14mu}\left( Q_{R\; 410A} \right)}} & (X) \\{\begin{matrix}{{Relative}\mspace{14mu}{performance}\mspace{14mu}{of}} \\{{coefficient}\mspace{14mu}\left( {RCOP}_{R\; 410A} \right)}\end{matrix} = \frac{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {COP}_{sample} \right)}{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu} R\; 410A\mspace{14mu}\left( {COP}_{R\; 410A} \right)}} & (Y)\end{matrix}$ wherein R410A is a mixture of difluoromethane andpentafluoroethane in a mass ratio of 1:1, and the sample is a workingfluid to be subjected to relative evaluation; the refrigerating capacityof each of the sample and R410A is an output (kW) when a standardrefrigerating cycle is operated under the following temperatureconditions (T) using each of the sample and R410A; and the coefficientof performance of each of the sample and R410A is a value obtained bydividing the above output (kW) by the power consumption (kW) requiredfor the above operation using each of the sample and R410A; [Temperatureconditions (T)] the evaporation temperature is 0° C., provided that inthe case of a non-azeotropic mixture, the evaporation temperature is theaverage temperature of the evaporation initiation temperature and theevaporation completion temperature, the condensing temperature is 40°C., provided that in the case of a non-azeotropic mixture, thecondensing temperature is the average temperature of the condensationinitiation temperature and the condensation completion temperature, thesupercooling degree (SC) is 5° C., and the degree of superheat (SH) is5° C.; (C-1): the relative pressure (RDP_(R410A)) calculated inaccordance with the following formula (Z) is at most 1.100:$\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{pressure}} \\\left( {RDP}_{R\; 410A} \right)\end{matrix} = \frac{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {DP}_{sample} \right)}{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu} R\; 410\; A\mspace{14mu}\left( {DP}_{R\; 410\; A} \right)}} & (Z)\end{matrix}$ wherein R410A is a mixture of difluoromethane andpentafluoroethane in a mass ratio of 1:1, and the sample is a workingfluid to be subjected to relative evaluation; the compressor dischargegas pressure of each of the sample and R410A is a compressor dischargegas pressure when a standard refrigerating cycle is operated under theabove temperature conditions (T) using each of the sample and R410A;(D-1): the lower limit of the combustion range measured in accordancewith method A in High Pressure Gas Safety Act is at least 5 vol %; and(E-1): in a combustion test under conditions of 0.98 MPaG and 250° C. inequipment in accordance with method A for measurement of the combustionrange in High Pressure Gas Safety Act, the pressure will not exceed 2.00MPaG.
 2. The working fluid according to claim 1, wherein the product ofthe relative coefficient of performance (RCOP_(R410A)) and the relativerefrigerating capacity (RQ_(R410A)) is at least 0.900.
 3. The workingfluid according to claim 2, wherein the product of the relativecoefficient of performance (RCOP_(R410A)) and the relative refrigeratingcapacity (RQ_(R410A)) is at least 0.950.
 4. The working fluid accordingto claim 1, wherein the relative pressure (RDP_(R410A)) is at most1.000.
 5. The working fluid according to claim 1, wherein the workingfluid has no combustion range.
 6. A composition for a heat cycle system,the composition comprising the working fluid for heat cycle as definedin claim 1 and a refrigerant oil.
 7. A heat cycle system, comprising thecomposition of claim
 6. 8. The heat cycle system according to claim 7,wherein the heat cycle system is a refrigerating apparatus, anair-conditioning apparatus, a power generation system, a heat transportapparatus or a secondary cooling machine.
 9. A working fluid for heatcycle, the working fluid being one of mixtures of:1,1,2-trifluoroethylene (HFO-1123), 2,3,3,3-tetrafluoropropene(HFO-1234yf), and difluoromethane (HFC-32); 1,1,2-trifluoroethylene(HFO-1123), trans-1,3,3,3,-tetrafluoropropene (HFO-1234ze(E)), anddifluoromethane (HFC-32); cis-1,2-difluoroethylene (HFO-1132(Z)) anddifluoromethane (HFC-32); trans-1,2-difluoroethylene (HFO-1132(E)),2,3,3,3-tetrafluoropropene (HFO-1234yf), and difluoromethane (HFC-32);or 1,1,2-trifluoroethylene (HFO-1123) and 2,3,3,3-tetrafluoropropene(HFO-1234yf), wherein the working fluid satisfies the followingproperties (A-1) to (E-1): (A-1): the global warming potential (100years) in Intergovernmental Panel on Climate Change (IPCC), Fourthassessment report, is at most 200; (B-1): the product of the relativerefrigerating capacity (RQ_(R410A)) calculated in accordance with thefollowing formula (X) and the relative coefficient of performance(RCOP_(R410A)) calculated in accordance with the following formula (Y)is at least 0.820: $\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{refrigerating}} \\{{capacity}\mspace{14mu}\left( {RQ}_{R\; 410A} \right)}\end{matrix} - \frac{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( Q_{sample} \right)}{{Refrigerating}\mspace{14mu}{capacity}\mspace{14mu}{of}\mspace{14mu} R\; 410{A\left( Q_{R\; 410A} \right)}}} & (X) \\{\begin{matrix}{{Relative}\mspace{14mu}{performance}\mspace{14mu}{of}} \\{{coefficient}\mspace{14mu}\left( {RCOP}_{R\; 410A} \right)}\end{matrix} - \frac{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {COP}_{sample} \right)}{{Coefficient}\mspace{14mu}{of}\mspace{14mu}{performance}\mspace{14mu}{of}\mspace{14mu} R\; 410{A\left( {COP}_{R\; 410A} \right)}}} & (Y)\end{matrix}$ wherein R410A is a mixture of difluoromethane andpentafluoroethane in a mass ratio of 1:1, and the sample is a workingfluid to be subjected to relative evaluation; the refrigerating capacityof each of the sample and R410A is an output (kW) when a standardrefrigerating cycle is operated under the following temperatureconditions (T) using each of the sample and R410A; and the coefficientof performance of each of the sample and R410A is a value obtained bydividing the above output (kW) by the power consumption (kW) requiredfor the above operation using each of the sample and R410A; [Temperatureconditions (T)] the evaporation temperature is 0° C., provided that inthe case of a non-azeotropic mixture, the evaporation temperature is theaverage temperature of the evaporation initiation temperature and theevaporation completion temperature, the condensing temperature is 40°C., provided that in the case of a non-azeotropic mixture, thecondensing temperature is the average temperature of the condensationinitiation temperature and the condensation completion temperature, thesupercooling degree (SC) is 5° C., and the degree of superheat (SH) is5° C.; (C-1): the relative pressure (RDP_(R410A)) calculated inaccordance with the following formula (Z) is at most 1.100:$\begin{matrix}{\begin{matrix}{{Relative}\mspace{14mu}{pressure}} \\\left( {RDP}_{R\; 410A} \right)\end{matrix} - \frac{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu}{sample}\mspace{14mu}\left( {DP}_{sample} \right)}{{Compressor}\mspace{14mu}{discharge}\mspace{14mu}{gas}\mspace{14mu}{pressure}\mspace{14mu}{of}\mspace{14mu} R\; 410{A\left( {DP}_{R\; 410A} \right)}}} & (Z)\end{matrix}$ wherein R410A is a mixture of difluoromethane andpentafluoroethane in a mass ratio of 1:1, and the sample is a workingfluid to be subjected to relative evaluation; the compressor dischargegas pressure of each of the sample and R410A is a compressor dischargegas pressure when a standard refrigerating cycle is operated under theabove temperature conditions (T) using each of the sample and R410A;(D-1): the lower limit of the combustion range measured in accordancewith method A in High Pressure Gas Safety Act is at least 5 vol %; and(E-1): in a combustion test under conditions of 0.98 MPaG and 250° C. inequipment in accordance with method A for measurement of the combustionrange in High Pressure Gas Safety Act, the pressure will not exceed 2.00MPaG.
 10. The working fluid according to claim 9, wherein the workingfluid is one of mixtures of: 1,1,2-trifluoroethylene (HFO-1123),2,3,3,3-tetrafluoropropene (HFO-1234yf), and difluoromethane (HFC-32);1,1,2-trifluoroethylene (HFO-1123), trans-1,3,3,3,-tetrafluoropropene(HFO-1234ze(E)), and difluoromethane (HFC-32); or1,1,2-trifluoroethylene (HFO-1123) and 2,3,3,3-tetrafluoropropene(HFO-1234yf).